Rock-drill.



PATENTED SEPT. 6, 1904..

W. BRADY.

ROCK DRILL.

APPLICATION FILED DEO.17,1903.

N0 MODEL.

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; aK W 74% GLVLJ; 000% MM 456 %%/mi W UNITED STATES Patented September 6, 1904.

PATENT OFFICE.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 769,465, dated September 6, 1904.

Application filed December 1'7, 1903. Serial No- 185,486. (No model.)

To u/ZZ whom, 1'25 may concern/.-

Be it known that LIVILLIAM BRADY, a citizen of the United States, residing in the city and county of San Francisco and State of California, have invented new and useful Improvements in Rock-,l h'ills, of which the following is a specification.

My invention relates to improvements in apparatus which is designed for striking blows in rapid succession, as in drilling rock, oper ating hammers or stamps, or for any like purposes.

It consists in the combination,with the part to be impelled, of cylinders fixed in line with each other having a piston -rod common to both connected with the impelled part and pistons fixed to the pistonrod within each cylinder. A forward impulse is given to these pistons alternately by a suitable medium under pressure and means are provided for rcturning the implement and pistons after the stroke has been completed by the momentum of the apparatus as transmitted through suitable flywheels carried thereby.

Referring to the accompanying drawings, Figure 1 is a plan view of drill, showing my invention. Fig. 2 is a portion of same, showing modification.

As shown in the accompanying drawings,

A and B are two cylinders connected together and in line with each other, having an intermediate space between them. These cylinders have pistons reciprocable within them, a piston-rod common to both and extending outwardly through one of the cylinder-heads and connected with a head, as at 2, this head being adapted to carry a drill or other device, as at 3, for striking blows.

As shown in my present invention, the pistons are designed to be impelled by an explosive vapor, such as that of gasolene, and suitable valves, as at i, are provided for the admission of the explosive mixture at the proper intervals. Exhaust-passages 5 are properly located to allow the expulsion of the products of explosion after the stroke has been completed, and any suitable or well-known devices may be employed for igniting the charges when compressed after the cylinders have been filled in the manner well known for this class of engines, this being not further explained, as it is no part of my present invention.

A shaft 6 is journalcd across the apparatus.

9 is a sprocket-wheel fixed upon the end of the shaft 6, and an endless chain 10 passing around this sprocket wheel extends rearwardly and passes around another sprocketwheel, 11, fixed upon a shaft 12, which is suitably journaled across the machine, as shown. The sprocket 11 is half the size of sprocket 9, so that through connections hereinafter described the proper movement of the exhaust-valves and other parts will be effected. Upon this shaft 12 are fly wheels, as shown at 13. These tly wheels have a sufficient weight to continue by their momentum the movement of the parts, so that after having received an impulse by which they are set in motion, they will continue to move while the pistons are returning for another stroke.

1% represents crank pins fixed to the flywheels or connected with the shaft.

15 represents rods extending forwardly and having their front ends connected with a crossbar 16. This cross-bar is slidable upon the drill shank or carrier and in front of the drill head or chuck 2, and the movements of the parts are so timed that the cross-head will be forced for ward with the revolution of the shaft 12 and wheels 13, so thatat the instant of the explosive action upon the pistons, by which the drill or equivalent striking apparatusis impelled forward, the cross bar will be moved to its farthest forward position, thus allowing the drill to be moved and to strike its blow with full force. The momentum of the fly-wheels 13, connected through the rods 15 upon the cross-bar 16, will draw it back, sliding upon the drill-shank until it contacts with the cushion 17 upon the front end of the drill head or chuck 2, and this acts to force the drill-head, connecting parts, and the pistons in the cylinders back to the rear ends, thus first expelling the gases resulting from the previously-exploded charge in one cylin der and charging the other cylinder in readiness for explosion. The cushion 17 relieves the shock of the returning cross-bar when it strikes the drill-head. By this means the return movement of the drill, which would otherwise have to be provided for by some independent mechanism, is made automatic, and the slidability and independent movement of the cross-head 16 with relation to the parts impelled by the pistons provides for a sulficient movement to the drill or its equivalent and the return of the drill to be afterward effected by the contact of the cross-bar with the drill-head, as previously described.

The igniters and exhaust-valves 4E and 5 are actuated as follows: A disk 7 is fixed on the shaft 6, and this disk has a crank-pin 21 and connecting-rod 20, extending back substantially parallel with the cylinders. This rod is reciprocated by the crank-pin, and it carries contact bars or lifters 23, which engage with arms 24, projecting from the exhaustvalve stems, so that they will be engaged by these lifters 23 to alternately actuate the valves in proper relation with the movements of the pistons.

It will be understood that the proportion of the sprockets 9 and 11 with relation to each other will be such as to properly time the movements of the exhaust-valves and the ignition devices with reference to the reciprocations of the pistons. The inlet-valves may be opened by suction.

If a fly-wheel is fixed upon the shaft 6, as shownin my former patent, No. 740, 800, dated October 6, 1908, the second shaft 12 and the connecting-rods 15 may be omitted and the crank l4 transferred to the shaft 6. The connection between the crank and the drill-head may be made in this case by means of a loose chain 15, extending from a loose sleeve on the crank to a fixed connection on the drillhead. The revolution of the crank slackens the chain at the instant the drill strikes the rock and allows the drill to impart its blow, and the momentum of the fly-wheel returns the crank and through the chain draws the drill back and returns the parts, as previously described.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

1. The combination in an apparatus for striking blows, of cylinders fixed axially in line, pistons movable in the cylinders having a piston-rod common to both and extending through the end of one of the cylinders, a tool-carrying head fixed to the piston-rod, a device for returning the parts after each stroke, said device having one end adapted to reciprocate in line with the tool-head, a journal-shaft having cranks with which the rear end of said device is connected, a fly-wheel carried by said shaft, and receiving motion from the impulses of the engine, the momentum of said fly-wheel acting through the crank-shaft connections to retract the drill and pistons after the latter has been impelled forward.

2. A reciprocating apparatus consisting of cylinders in line with each other having pistons movable in each, a piston-rod common to both, and a drill or like head with which the piston-rod connects, inlet and exhaust valves connected with the rear of the cylinders, a mechanism by which the pistons are automaticallymoved to the rear of the cylinders to alternately compress an explosive charge and to expel residual products, said mechanism consisting of parallel journaled shafts transverse to the cylinders, fly-wheels fixed upon one of said shafts, sprocket-wheels upon both shafts and an endless chain connecting them, and mechanism whereby the second shaft is rotated, said mechanism consisting of cranks connected and movable with a cross-head slidable with relation to the drill and its head.

3. The combination in a rock-drill of a plurality of power-cylinders having pistons movable therein, a drill-head with which the pistons are connected. a drill carried by said head and movable in unison therewith, mechanism by which the parts are returned after a stroke has been delivered, said mechanism consisting of a cross-head connected and reciprocable in line with the drill, parallel shafts journaled transverse to the cylinders, said shafts having sprocket-wheels, an endless connecting-chain, flywheels mounted upon one of the shafts, cranks, and connecting-rods extending from the cranks to the cross-head, and a cushion interposed between the cross-head and the drillhead against which the cross-head contacts upon its return movement.

L. The combination with a rock-drill and mechanism connected therewith whereby the drill is impelled and a blow given by an explosion at the rear thereof, of means for automatically returning the drill after the explosion, said means consisting of a cross-head slidable upon the drill-shank, a cushion interposed between said cross-head and the drillhead against which said cross-head impinges upon its return movement and by which it retracts the drill and its actuating mechanism, a shaft having fly-wheels and cranks, and connecting-rods between said cranks and the ends of the cross-head, a second shaft parallel with the first-named shaft, sprocket-wheels upon both shafts and an endless chain whereby motion is transmitted between the two, a crank mounted upon the second shaft, and connections between said crank and the exhaustvalves whereby motion is transmitted between said reciprocating and revoluble parts.

5. The combination in a rock-drill of. a plurality of cylinders axially in line, having pistons and a piston-rod connected with both pistons and with a drill-carrying head exterior to one of the cylinders, inlet and exhaust valves to each of said cylinders, a rod having toes or lifters engaging corresponding arms upon the exhaust-valve stems, a shaft journaled transversely to the engine-cylinders,

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said shaft carrying a fiy-Wheel, a crank with which the valveactuating rod is connected, a crank upon the fly-wheel shaft, and connection between said crank and a cross-head, whereby the momentum of the fiy-wheels is transmitted to advance the cross-head to allow l a free movement of the drill under the explosive action within the cylinders, and a cushion 1 upon the drill-head against which the cross- 10 head impinges and by which the drill and reciprocating pistons are automatically retracted.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

lVlLLIAM BRADY.

Witnesses:

S. H. NoURsn, GEORGE PA'LTISON. 

